add a test on json response generation
add a test on json response generation

create a json response based on test file and compare it to expected
response.
comparison first checks that there is no missing or extra key
and then compares keys

Signed-off-by: EstherLerouzic <9136e9bbec0a09a1685b8ebbe677b6c9b26e8f18@orange.com>

Telecominfraproject/gnpy